The facile preparation of g-C3N4 QDs with high fluorescent performance has become an important direction in the last decade. Herein, we develop a facile, rapid approach to synthesize highly fluorescent QDs based on re...The facile preparation of g-C3N4 QDs with high fluorescent performance has become an important direction in the last decade. Herein, we develop a facile, rapid approach to synthesize highly fluorescent QDs based on recrystallization and ultrasonic exfoliation. Size-controllable graphitic carbon nitride(gC3N4) QDs can be obtained from the precursor of recrystallized dicyandiamide, only 90 min is needed and the size of QDs is adjusted from 5 nm to 200 nm by controlling the ultrasonic time. Moreover, better fluorescent efficiency is also obtained comparing to traditional g-C3N4 QDs. The obtained g-C3N4 QDs responds to Cu(Ⅱ) in the 0.5 nmol/L to 30 μmol/L concentration range, with a 0.3 nmol/L detection limit.The method was applied to the determination of Cu(Ⅱ) in different environmental water samples.展开更多
Shallow conductive heterogeneity can lead to static shifts ain the apparent resistivity sounding curve of controlled-source audio-frequency magnetotellurics(CSAMT).The static effect will shift the apparent resistivity...Shallow conductive heterogeneity can lead to static shifts ain the apparent resistivity sounding curve of controlled-source audio-frequency magnetotellurics(CSAMT).The static effect will shift the apparent resistivity curves along with axial log-log coordinates.Such an effect,if not properly processed,can distort the resistivity of rock formation and the depth of interfaces,and even make the geological structures unrecognizable.In this paper,we discuss the reasons and characteristics of the static shift and summarize the previous studies regarding static shift correction.Then,we propose the Guided Image Filtering algorithm to suppress static shifts in CSAMT.In detail,we use the multi-window superposition method to superimpose 1D signals into a 2D matrix image,which is subsequently processed with Guided Image Filtering.In the synthetic model study and field examples,the Guided Image Filtering algorithm has effectively corrected and suppressed static shifts,and finally improved the precision of data interpretation.展开更多
基金the support from the National Natural Science Foundation of China (No. 21605052)the Special Support Program of Guangdong Province (No. 2016TQ03R749)+1 种基金the Special Project of Science and Technology Development of Guangdong Province (No. 2017B020207011)the Guangdong Natural Science Foundation (No. 2016A020221030)
文摘The facile preparation of g-C3N4 QDs with high fluorescent performance has become an important direction in the last decade. Herein, we develop a facile, rapid approach to synthesize highly fluorescent QDs based on recrystallization and ultrasonic exfoliation. Size-controllable graphitic carbon nitride(gC3N4) QDs can be obtained from the precursor of recrystallized dicyandiamide, only 90 min is needed and the size of QDs is adjusted from 5 nm to 200 nm by controlling the ultrasonic time. Moreover, better fluorescent efficiency is also obtained comparing to traditional g-C3N4 QDs. The obtained g-C3N4 QDs responds to Cu(Ⅱ) in the 0.5 nmol/L to 30 μmol/L concentration range, with a 0.3 nmol/L detection limit.The method was applied to the determination of Cu(Ⅱ) in different environmental water samples.
基金sponsored by the Basic Science Center Project of National Natural Science Foundation of China(72088101)。
文摘Shallow conductive heterogeneity can lead to static shifts ain the apparent resistivity sounding curve of controlled-source audio-frequency magnetotellurics(CSAMT).The static effect will shift the apparent resistivity curves along with axial log-log coordinates.Such an effect,if not properly processed,can distort the resistivity of rock formation and the depth of interfaces,and even make the geological structures unrecognizable.In this paper,we discuss the reasons and characteristics of the static shift and summarize the previous studies regarding static shift correction.Then,we propose the Guided Image Filtering algorithm to suppress static shifts in CSAMT.In detail,we use the multi-window superposition method to superimpose 1D signals into a 2D matrix image,which is subsequently processed with Guided Image Filtering.In the synthetic model study and field examples,the Guided Image Filtering algorithm has effectively corrected and suppressed static shifts,and finally improved the precision of data interpretation.
